Ningbo Fuda 5250B Dehumidifier

Ningbo Fuda 5250B Dehumidifier

Device Type: misc
Electrical Standard: global
Board: esp8266
Difficulty: Plug-n-flash, 2/5

The 5250B dehumidifier

Ningbo Fuda Intelligent Technology is a company manufacturing a number of devices such as dehumidifiers and air conditioning units. These are typically white-labeled, and come under a number of brand names such as Rohnson, Nedis, Kayami, Cling etc.

Some of these dehumidifiers are WiFi-enabled, by employing a Tuya module, allowing them to be fully controlled over WiFi, typically using the vendor's smartphone app, or the Tuya Smart/Smart Life applications.

Unfortunately, as of October 2023, ESPHome does not include a Humidifier/Hygrostat component to map to Home Assistant's Humidifier integration (see esphome/feature-requests#1859). Until such support is added, the dehumidifier can be exposed as a series of switches, sensors and selects, for each of the functions of the device's control panel.



It is often possible to use tuya-convert to flash the module over-the-air. Note that this applies to ESP8266-based modules; if your model shipped with a BK72xx-based module, other methods such as tuya-cloudcutter can be used.

Both of these tools rely on exploiting vulnerabilities in the stock Tuya firmware, which may be patched in newer versions, so this may or may not work with your device. It is generally advisable to not install firmware updates through the vendor's smartphone application as this may patch any vulnerabilities that exist in the shipped software.

Over serial

If OTA fails, it is possible to flash the module through the serial port pins, using esptool, or, in case your model shipped with a BK72xx, using ltchiptool.

The dehumidifier can be easily disassembled using a Philips screwdriver. The Tuya module can be found on a separate daughterboard, connected using a JST connector to the mainboard, which provides the board with +5V, GND, as well as RX/TX pins for the UART connecting to the main MCU. The daughterboard includes a voltage regulator and level shifters to convert between +5V and +3.3V, that the Tuya module expects. Unfortunately, this is a different UART than the one required for flashing the firmware. However, the daughterboard helpfully contains debug pins next to the module:

PinConnect to
UART 0 RXSerial adapter TXD
IO1Serial adapter RXD
IO0Short to GND for flashing
GNDSerial adapter/Vcc GND

Vcc needs to be provided separately, either +5V through the connector, or +3.3V directly to the ESP8266.

Board Configuration

The configuration below is for a Rohnson R-9820, model name FDD20-5250BWR5:

board: esp_wroom_02
rx_pin: GPIO13 # U1RX
tx_pin: GPIO15 # U1TX
baud_rate: 9600
- sensor_datapoint: 11
datapoint_type: bitmask
- lambda: |-
ESP_LOGD("main", "on_datapoint_update %s", format_hex_pretty(x).c_str());
// only seen in the wild is decimal value 8, for Water Tank Full
id(water_tank_full).publish_state((x >> 3) & 1);
- platform: template
id: water_tank_full
name: "Water tank"
device_class: problem
icon: "mdi:water-alert"
- platform: tuya
name: "Unknown 101"
sensor_datapoint: 101
internal: true
- platform: tuya
name: "Unknown 105"
sensor_datapoint: 105
internal: true
- platform: tuya
name: "Power"
switch_datapoint: 1
- platform: tuya
name: "Air clean"
icon: "mdi:leaf"
switch_datapoint: 5
- platform: tuya
name: "Child lock"
icon: "mdi:lock"
switch_datapoint: 7
- platform: tuya
name: "Sleep"
icon: "mdi:sleep"
switch_datapoint: 102
- platform: tuya
name: "Target humidity"
number_datapoint: 4
unit_of_measurement: "%"
device_class: "humidity"
min_value: 30
max_value: 80
step: 5
- platform: tuya
name: "Temperature"
sensor_datapoint: 103
unit_of_measurement: "°C"
device_class: "temperature"
accuracy_decimals: 0
- platform: tuya
name: "Humidity"
sensor_datapoint: 104
unit_of_measurement: "%"
device_class: "humidity"
accuracy_decimals: 0
- platform: tuya
name: "Mode"
icon: "mdi:cog"
enum_datapoint: 2
0: Regular
1: Automatic
2: Strong
3: Clothes drying
- platform: tuya
name: "Fan speed"
icon: "mdi:fan"
enum_datapoint: 6
0: Low
1: High
# - platform: tuya
# name: "Unknown"
# enum_datapoint: 12
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